U.S. Pat. No. 4,838,968 and U.S. Ser. No. 364,452 filed Jun. 12, 1989 now U.S. Pat. No. 4,954,202 each commonly assigned, disclose a method and apparatus for making V-grooved insulation from rigid material. As disclosed therein, a rigid, or semi-rigid board, such as mineral wool, is carried by a conveyor through a series of steps wherein a backing material is applied to one surface of the board and the board subsequently automatically V-grooved with a series of V-grooves, with the V-grooves extending up to but not severing the backing layer. The disclosed apparatus and process permits the manufacture of V-groove insulation wherein the spacing of the V-grooves can be varied and controlled in order that diameters. The '968 patent and the aforesaid application do not disclose layered or composite materials.
Various forms of layered sheet materials are, however, described in the art which can conform to the shape of another material, for example, insulation material conforming to the shape of a pipe. It has been difficult and impractical heretofore to provide a material which will readily and smoothly conform to a given surface and which also is easily managed in storage and shipment prior to use. Unless separate sheets are layered upon one another at the time of installation, an insulation covering has essentially been of one material having a single insulation property.
More specifically, U.S. Pat. No. 4,576,206 describes a semi-cylindrical pipe insulation sleeve made up of an outer layer of mineral wool and an inner layer of mineral wool. The insulation sleeve is made utilizing a mold. First, an outer layer is formed containing V-shaped slits therein. The outer layer is hardened and placed in a mold for a semi-cylindrical sleeve. At this point, the V-shaped slits are closed. The inner layer, which is initially flexible, is hardened after placement in the inner surface of the outer layer in the mold. A thermosetting binder is used to harden the layers. The binder additionally holds the two layers together following a heat treatment of the layers. In addition to the complexity of manufacture, due to the semi-cylindrical shape of the insulation sleeve with two sleeves being necessary to encompass a pipe, shipping due to space requirements is not economical.
To the extent the art discloses other layered sheet materials useful as an insulation material, those sheet materials have only a single layer of material having insulating properties. The other layer or layers present merely serve as backing or boundaries to maintain the integrity of the insulation material. For example, U.S. Pat. No. 3,557,840 describes a sandwich insulation board having a core of rigid cellular plastic foam and two outer deformable skin surfaces which effectively act as mold surfaces. The foam is formed in situ between the deformable skins or mold surfaces. The skin surfaces which can be a polymeric material, paper, wood sheeting, dry or asphalt saturated felts, or wood or batting fibers do not have substantial insulative property, and are not intended to be insulating materials. "Insulating materials" as used herein means a material having low heat conductivity and able to withstand high temperatures without degradation or destruction.
Where individual strips or sections have been utilized to form a unitary sheet material, the sections are each made of the same insulative material and do not form a composite material. The backing material utilized to hold the segments together again does not have substantial insulating properties. For example, U.S. Pat. Nos. 2,776,231 and 2,890,739 describe segmented insulating coverings for pipes or the like made up of two facing layers and an inner insulative layer. The first outer layer is a web material such a kraft paper and the second outer layer is a material such as aluminum foil. The inner layer is made up of parallel segments of either foam glass or baked cork having a prismatic or truncated configuration which are adhered to the other layers by an adhesive. The prismatic or truncated shapes allow for the folding of the insulating material around a pipe.
The use of wire as an integral part of an insulating sheet has been described in the art as reinforcement for the insulation material. In U.S. Pat. No. 1,734,209, a pipe insulating jacket made up of rock wool and a backing is described. Grooves are formed in the insulating material. Reinforcements, such as a wire mesh or stapling, are positioned in the rock wool so that the reinforcements extend from the backing to the opposite surface of the insulation material. Wire integral with a composite V-grooved material is not disclosed in the art for fastening the composite together or to another structure. The fastening of a sheet material to another structure to which the sheet material conforms has conventionally used an adhesive flap at one end of the sheet material, or the like, for example as described in U.S. Pat. Nos. 2,890,739 and 3,117,902.
The art also does not disclose the use of or the advantages of an adhesive applied to a V-grooved material in a selective manner to provide a hinge. U.S. Pat. No. 3,084,403 teaches the use of a hinged structure with a normally rigid grooved material. However, the hinge is provided by the backing which is inserted into the grooves formed in the rigid material and not through the selective placement of adhesive in the grooves. Otherwise, the art discloses the use of an adhesive to cover an entire surface to prevent separation of material. For example, U.S. Pat. No. 4,576,706, as described above, uses a binder sprayed indiscriminately on the insulation material to maintain the V-shaped slits closed.